Polymer solution and dispersion and a process for the preparation thereof

Abstract

A polymer dispersion or solution containing a hydrophobic polysaccharide, which is dispersed or dissolved in liquid phase, and plasticizer composition of the polysaccharide, whereby at least 10% by weight of the plasticizer composition is formed from alkenyl succinic anhydride. The invention also relates to the preparation of polymer dispersions and solutions and to the films and coatings produced from them. The dispersions according to the invention are stable, and coating with excellent film-forming properties can be prepared from them.

1. A polymer dispersion or solution containing a hydrophobic polysaccharide selected from the group consisting of cellulose acetate and starch acetate, which is dispersed or dissolved in liquid phase, and a plasticizer for the polysaccharide, wherein at least 10% by weight of the plasticizer consists of alkenyl succinic anhydride or alkenyl succinate. 
     
     
       2. The polymer dispersion or solution according to  claim 1 , wherein the alkenyl succinic anhydride has the formula (I) 
       
         
           
           
               
               
           
         
       
       wherein R is a linear or branched alkenyl group having 3-24 carbons. 
     
     
       3. The polymer dispersion or solution according to  claim 1 , wherein the alkenyl succinate has the formula (II) 
       
         
           
           
               
               
           
         
       
       wherein R is a linear or branched alkenyl group having 3-24 carbons, and R 1  and R 2  can be, independent of each other, hydrogen or a linear or branched alkyl or alkenyl group, which has 1-10 carbons and which can have one or more functional groups. 
     
     
       4. The polymer dispersion or solution according to any of the preceding claims, wherein the plasticizer constitutes 10-70% by weight of the dry content of the dispersion or the solution. 
     
     
       5. The polymer dispersion or solution according to  claim 1 , wherein the plasticizer contains a second plasticizing component, which is triacetin, diacetin, monoacetin, triethyl citrate, tributyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, dimethyl succinate, diethyl succinate, oligo esters of succinic acid and diols, ethyl lactate, methyl lactate, fatty acid esters of glycerol, castor oil, olive oil, rapeseed oil, tall oil, dibutyl phthalate, diethyl phthalate or a mixture thereof. 
     
     
       6. The polymer dispersion or solution according to  claim 5 , wherein the plasticizer contains an oligomeric plasticizing agent. 
     
     
       7. The polymer dispersion or solution according to  claim 5 , wherein the second plasticizing component constitutes, in the dispersion, 5-90%. 
     
     
       8. The polymer dispersion or solution according to  claim 1 , wherein the starch acetate contains cationic groups. 
     
     
       9. The polymer dispersion or solution according to  claim 1 , wherein the polysaccharide derivative is ethyl cellulose. 
     
     
       10. The polymer dispersion or solution according to  claim 1 , wherein the anhydride of alkenyl succinate is an anhydride of n-octenyl alkenyl succinate. 
     
     
       11. A polymer coating/coating for pharmaceutical preparations containing polysaccharides and/or polysaccharide derivatives selected from the group consisting of cellulose ethers, cellulose esters, starch ethers, and starch esters, wherein the plasticizer of the polymer contains an anhydride of alkenyl succinate or an alkenyl succinate. 
     
     
       12. The polymer coating according to  claim 11 , wherein the water vapour transmission rate of the coating is less than 300 g/m 2  in 24 h and Cobb60, the number describing the water absorption, is less than 3 g/m 2 , while the amount of coating is at least 30 g/m 2 . 
     
     
       13. A polymer dispersion or solution containing a hydrophobic polysaccharide selected from the group consisting of cellulose ether, cellulose ester, starch ether, or starch ester, which is dispersed or dissolved in liquid phase, and a plasticizer for the polysaccharide, wherein at least 10% by weight of the plasticizer consists of alkenyl succinic anhydride or alkenyl succinate.